Ethylene glycol is found most commonly in antifreeze, automotive cooling systems, and hydraulic brake fluid. In an industrial setting it is also used as a solvent and in a variety of processes.

Many cases of ethylene glycol poisoning are due to the accidental ingestion of it by children. They may take in large amounts since the substance tastes good. Alcoholics may also drink it as a substitute for alcohol (ethanol).

Ethylene glycol is itself relatively nontoxic. However, it is metabolized (changed) in the body by the enzyme alcohol dehydrogenase into glycolic acid, glyoxylic acid and oxalic acid, which are highly toxic compounds.

Renal failure, acidosis and hypocalcemia may follow the intake of ethylene glycol. There can be widespread tissue injury in the kidney, brain, liver, and blood vessels. The result can be fatal.

The traditional treatment of ethylene glycol poisoning has been ethanol which competes for the attention of the enzyme (as a competitive substrate of alcohol dehydrogenase) and hemodialysis which removes ethylene glycol and its toxic metabolites from the blood. A new alcohol dehydrogenase inhibitor, fomepizole (brand name: Antizol), was approved in 1997 for the treatment of ethylene glycol poisoning in patients at least 12 years old. It has also been used successfully with younger children.